The present invention pertains generally to medical equipment and more particularly to an atherectomy catheter having an ultrasound transmission member extending therethrough such that ultrasonic energy may be delivered to the distal end of the catheter to facilitate the atherectomy procedure.
The prior art has included a number of ultrasonic catheters which are insertable into the mammalian body and usable to deliver ultrasonic energy for purposes of ablating obstructive material from anatomical cavities or passageways, or for other therapeutic purposes.
Examples of ultrasonic treatment catheters and related apparatus include those described in U.S. Pat. No. 3,433,226 (Boyd), U.S. Pat. No. 3,823,717 (Pohlman, et al.), U.S. Pat. No. 4,808,153 (Parisi), U.S. Pat. No. 4,936,281 (Stasz), U.S. Pat. No. 3,565,062 (Kuris), U.S. Pat. No. 4,924,863 (Sterzer), U.S. Pat. No. 4,870,953 (Don Michael, et al.), U.S. Pat. No. 4,920,954 (Alliger, et al.), U.S. Pat. No. 5,267,954 (Nita), as well as other patent publications W087-05739 (Cooper), W089-06515 (Bernstein, et al.), W090-0130 (Sonic Needle Corp.), EP316789 (Don Michael, et al.), DE3,821,836 (Schubert) and DE2,438,648 (Pohlman).
Additionally, ultrasound transmitting catheters may be utilized to deliver ultrasonic energy to mammalian blood vessels for the purpose of preventing or reversing vasospasm, as described in U.S. Pat. No. 5,324,255.
The prior art has also included a number of atherectomy devices which are insertable into blood vessels and usable to cut, shave or otherwise sever obstructive matter from the walls of the blood vessel. Such atherectomy devices typically include aspiration channels for suctioning the severed matter from the lumen of the blood vessel. Examples of atherectomy devices which have heretofore been know include those described in U.S. Pat. Nos. 5,100,423 (Fearnot),
Additionally, U.S. Pat. No. 4,808,153 (Parisi) has described a device for removing placque from arteries wherein a hollow tip member is mounted on the distal end of a tubular catheter, and an ultrasound source is connected to the proximal end of the catheter to cause the entire catheter, including the distal tip, to undergo vibratory movement. Such vibratory movement of the hollow distal tip member ostensibly creates heat which serves to emulsify obstructive matter which is located on the walls of an artery adjacent the vibrating hollow tip member. The emulsified matter is subsequently suctioned or withdrawn, in the proximal direction, through the hollow tip member and through the lumen of the catheter.
Although the device described in U.S. Pat. No. 4,808,153 (Perisi) is purportedly useable to remove obstructive matter from the walls of a blood vessel, the device disclosed in such prior United States Patent is believed to be of less than optimal design for all intravascular applications. Accordingly, there remains a need for a new ultrasonic angioplasty catheter capable of utilizing ultrasound-induced vibratory motion to sever or separate obstructive matter from the walls of blood vessels or other anatomical passageways, and which includes means for promptly removing the severed or separated matter from the lumen of the blood vessel or anatomical passageway.
In accordance with the present invention, there is provided an ultrasonic device and method for removing obstructive matter from an anatomical cavity or passageway, such as a blood vessel. The device of the present invention generally comprises an elongate pliable catheter body having a distal tip member attached to the distal end thereof. An ultrasound transmission member, such as a metal wire, extends longitudinally through the catheter body to transmit ultrasonic vibratory movement from the proximal end of the catheter body, to the distal tip member. In this regard, the proximal end of the ultrasound transmission member is connectable to an ultrasonic transducer or other ultrasound generating device. The ultrasound transmission member is substantially unattached to the catheter body, such that the ultrasound transmission member may vibrate or move independent of the catheter body. The distal tip member may be attached to the distal end of the catheter body such that, ultrasonic vibratory movement transmitted to the distal tip member may also cause a distal portion of the catheter body to vibrate or move. A concave indentation is formed on the distal face of the distal tip member, and at least one aspiration passageway extends longitudinally through the distal tip member, from the distal face thereof to the proximal end thereof, in communication with a lumen of the catheter body such that matter which becomes located within the concave indentation of the distal tip member may be aspirated, in the proximal direction, through the aspiration passageway and through the catheter body. The ultrasonic device of the foregoing character insertable into the desired anatomical cavity or passageway (e.g., blood vessel) and advance to a point where the distal tip member is adjacent a quantity of obstructive matter to be removed. Thereafter, ultrasonic energy is passed through the ultrasound transmission member to the distal tip member, thereby causing ultrasonic vibratory movement of the distal tip member. The catheter is then further advanced such that the concave indentation in the distal face of the distal tip member comes in contact with the obstructive matter, and the ultrasonic vibratory movement of the distal tip member causes the obstructive matter to be separated or severed thereby. The separated or severed obstructive matter is then aspirated through the aspiration passageways, and through the catheter, thereby effecting complete removal of such matter.
Further in accordance with the invention, the elongate pliable catheter body of the ultrasonic device of the foregoing character may comprise an outer tube having a hollow lumen of a lumenal diameter, and an inner tube having an outer surface of an outer diameter. The inner tube is disposed within the lumen of the outer tube, and the distal ends of both tubes are affixed or positioned in abutment with the distal tip member. The aspiration passageway(s) of the distal tip member is in communication with the lumen of the inner tube, such that severed particles of obstructive matter may be suctioned through the aspiration passageway and through the lumen of the inner tube. Additional fluid infusion passageways may be formed through the distal tip member, in communication with the lumenal surface of the outer tube. In this regard, irrigation fluid, medicaments or other fluid may be infused through such lumenal space and out of the outlet passageway(s) formed in the distal tip member.
Further in accordance with the invention, there is provided a method of removing obstructive matter from an anatomical passageway, said method comprising the steps of:
a) providing an ultrasonic catheter device which comprises:
an elongate pliable catheter body having a proximal end, a distal end, and at least one lumen extending longitudinally therethrough;
a distal tip member attached to the distal end of said catheter body, said distal tip member having a distal surface, a concave indentation being formed in said distal surface;
an ultrasound transmission member extending longitudinally through said catheter body to transmit ultrasound from an ultrasound source located adjacent the proximal end of said catheter body, through said catheter body, to said distal tip member;
at least one aspiration passageway extending longitudinally through said distal tip member from the proximal surface thereof to the distal surface thereof, said aspiration passageway being in communication with a lumen of said catheter such that matter which becomes located within the concave indentation of said distal tip member may be aspirated, in the proximal direction, through said passageway and through said lumen of said catheter.
b) inserting said catheter body into said anatomical passageway wherein said obstructive matter is located;
c) advancing said catheter body to a point where said distal tip member is located adjacent the obstructive matter to be removed;
d) passing ultrasound through said ultrasound transmission member through said distal tip member, thereby causing said distal tip member to undergo ultrasonic vibratory movement;
e) advancing said catheter body such that the concaved distal surface of said distal tip member comes into contact with said obstructive matter, and such that the ultrasonic vibratory movement of said distal tip member facilitates severance of a portion of said obstructive matter; and
f) causing a severed portion of said obstructive matter to be aspirated in the proximal direction, through said aspiration passageway, and through a lumen of said catheter body.
Additionally the method may include the step of infusing irrigation fluid or medicaments into the region where the obstructive matter is located. Such infusion of irrigation fluid or medicaments may occur separately from, or contemporaneously with, the severing, separation and/or removal of the obstructive matter.
Further objects and advantages of the present invention will become apparent to those skilled in the art upon reading and understanding of the following detailed description and the accompanying drawings.